The present invention generally relates to the repair of punctured pneumatic tires, such as car and truck tires, and more particularly relates to the internal repair of such tires using a pressurized mixture of propellant gas and tire sealant material forced into a tire through its inflation valve.
Various small canister-type devices are currently available for roadside use by motorists to internally seal and inflate a vehicle tire which has gone completely flat due to a puncture therein. Conventional inflation/sealing canisters of this type are removably connectable to the inflation valve of the tire and are filled with a mixture of a propellant gas and a tire sealant compound under a relatively high pressure sufficient to the drive the sealant compound into the tire and fully inflate the tire. While this relatively simple method of do-it-yourself emergency roadside tire repair has proven to be a convenient and rapid alternative to changing the punctured tire, it is also subject to several well known problems, limitations and disadvantages.
For example, the desirably small size of these conventional inflation/sealing canisters, coupled with their designed-for capability of fully inflating a completely flat tire in addition to internally sealing a puncture therein, requires that the pre-use internal pressures of such canisters be relatively high. Typically, the pre-use internal pressure of a conventionally sized inflation/sealing canister is approximately 70-90 psig.
This relatively high internal pressure requirement increases the susceptibility of the canister to heat-created bursting. Accordingly, care must be taken to avoid prolonged exposure of the canister to hot environments such as on a car seat during a hot summer day.
Another problem associated with conventional inflation/sealing canisters relates to their propellant gases. Typically, one of two types of propellant gas are used - (1) a refrigerant-type hydrofluorocarbon gas (such as R-12, R-22, etc.), or (2) a methane-butane gas. As is now well known, refrigerant-type propellant gases are highly undesirable because of their ozone-depleting characteristics. While methane-butane propellant gases are non-ozone depleting, they are highly flammable and can thus present a safety hazard if care is not exercised in their use.
In view of the foregoing it can readily be seen that a need exists for improved methods and related apparatus for effecting the roadside repair of a flat vehicle tire that eliminates or at least substantially reduces the above-mentioned problems, limitations and disadvantages associated with conventional tire inflation/sealing canister devices of the type generally described above. It is accordingly an object of the present invention to provide such improved methods and related apparatus.